one of the definitions of the word "correspondent" is a person with whom one converses through writing: is there a corresponding ;-) word for a person with whom one converses vocally (either in person or via telecommunications)?
Correspondent, cor·re·spon·dent \ˌkȯr-ə-ˈspän-dənt, ˌkär-\ noun -MW
a person whose job is to send news to a newspaper, radio station, or television program often from different places around the world;
one who has regular commercial relations with another;
one who contributes news or commentary to a publication (as a newspaper) or a radio or television network often from a distant place